The Barnes maze is a dry-land based rodent behavioral paradigm for assessing spatial learning and memory that was originally developed by its namesake, Carol Barnes. It represents a well-established alternative to the more popular Morris Water maze and offers the advantage of being free from the potentially confounding influence of swimming behavior. Herein, the Barnes maze experimental setup and corresponding procedures for testing and analysis in mice are described in detail.

The human selenoprotein family contains 25 members that share the common feature of containing the amino acid, selenocysteine (Sec). Seven selenoproteins are localized to the endoplasmic reticulum (ER) and exhibit different structural features contributing to a range of cellular functions. Some of these functions are either directly or indirectly related to calcium (Ca) flux or homeostasis. The presence of the unique Sec residue within these proteins allows some to exert oxidoreductase activity, while the function of the Sec in other ER selenoproteins remains unclear. Some functional insight has been achieved by identifying domains within the ER selenoproteins or through the identification of binding partners. For example, selenoproteins K and N (SELENOK AND SELENON) have been characterized through interactions detected with the inositol 1,4,5-triphosphate receptors (IP3Rs) and the SERCA2b pump, respectively. Others have been linked to chaperone functions related to ER stress or Ca homeostasis. This review summarizes the details gathered to date regarding the ER-resident selenoproteins and their effect on Ca regulated pathways and outcomes in cells.

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The central nucleus of the amygdala (CeA) has been traditionally viewed in fear conditioning to serve as an output neural center that transfers conditioned information formed in the basolateral amygdala to brain structures that generate emotional responses. Recent studies suggest that the CeA may also be involved in fear memory consolidation. In addition, corticotropin-releasing factor systems were shown to facilitate memory consolidation in the amygdala, which contains a high density of CRF immunoreactive cell bodies and fibers in the lateral part of the CeA (CeAl). However, the involvement of CeA CRF in contextual fear conditioning remains poorly understood. Therefore, we first conducted a series of studies using fiber-sparing lesion and reversible inactivation methods to assess the general role of the CeA in contextual fear. We then used identical training and testing procedures to compare and evaluate the specific function of CeA CRF using CRF antisense oligonucleotides (CRF ASO). Rats microinjected with ibotenic acid, muscimol, or a CRF ASO into the CeA before contextual fear conditioning showed typical levels of freezing during acquisition training but exhibited significant reductions in contextual freezing in a retention test 48 h later. Furthermore, CeA inactivation induced by either muscimol or CRF ASO administration immediately before retention testing did not impair freezing, suggesting that the previously observed retention deficits were caused by inhibition of consolidation rather than fear expression. Collectively, our results suggest CeA involvement in the consolidation of contextual fear memory and specifically implicate CeA CRF as an important mediator.

Background: Selenoprotein M (SelM) is highly expressed in the brain and postulated to have neuroprotective properties. Results: SelM expression is present in high levels in hypothalamic nuclei involved in energy metabolism, and SelM KO mice exhibit increased adiposity without apparent cognitive deficits. Conclusion: SelM protects against obesity. Significance: Increased understanding of the genes that protect against obesity may yield improved treatments and prevention strategies.